Competing models of language evolution: what counts as evidence?

Whether language emerged suddenly in approximate synchrony with the Upper Paleolithic, suddenly at another point in time, or gradually over an extended period remains a matter of debate. Questions of how to define language, protolanguage, symbolism, and syntax profoundly influence evolutionary perspectives as do competing scientific frameworks regarding the degree of behavioral localization in the brain and the nature of the genetic changes needed to instill linguistic capacity. Profound disagreements also center on interpretations of fossil and archeological data. Some infer the presence or absence of language from the presence or absence of symbolic art or complex tools. However, some fully linguistic modern societies create little in the way of non-perishable artistic or technological remains, and clear links have yet to be shown between syntax and art, complex tools, or handedness. One bright point has, however, emerged. Linguists are now developing sophisticated models of how language could have evolved. It is time for others to develop equally sophisticated models of what we can actually determine about language from archaeological and fossil remains. This paper briefly discusses this issue from the perspective of comparative animal and human data on lateralization, complex object manipulations, and communication.